Non-Visual Components of Anomalous Head Posturing (AHP) In Patients with Infantile Nystagmus Syndrome (INS) AuthorBlock: Richard W. Hertle1, Cecily Kelleher1, David Bruckman2, Neil McNinch1, Isabel Alvim Ricker1, Rachida Bouhenni1 1Children's Hosp Medical Ctr of Akron, Hudson, Ohio, United States; 2Cleveland Clinic, Ohio, United States; DisclosureBlock: Richard W. Hertle, None; Cecily Kelleher, None; David Bruckman, None; Neil McNinch, None; Isabel Alvim Ricker, None; Rachida Bouhenni, None; Purpose To investigate the visual and non-visual etiologies of anomalous head posturing in patients with INS.Methods This is a prospective, cohort analysis of clinical and AHP data in 34 patients with INS. Data collected included routine demography and surgical procedure. Main outcome measures included: 1) binocular, best-corrected, LogMAR visual acuity in the null position (BVA), 2) AHP in degrees while measuring best-corrected binocular acuity, 3) AHP in degrees while being prompted to position their head in “the most comfortable position.” 4) response to question regarding their subjective sense of straight in their AHP and 5) with their head straight. Paired t-test was used to determine significance in objective vs. subjective AHP.Results Age ranged from 10-51 yrs (mean 16.5 yrs). 56% were male. 53% had BVA > 20/40. Associated systemic or ocular system deficits were present in 88%, including; developmental delay (12%), neuropsychiatric disease (29%), albinism (50%), strabismus (32%), amblyopia (24%), optic nerve and/or retinal disease (44%) and refractive error (94%), 74% (25 pts) had eye movement recording confirmed eccentric null position and a > 10 degree AHP, 15% (5 pts) had a periodic or aperiodic component. Mean AHP of all patients during BVA testing was (-0.88 roll, -3.35 pitch, -4.18 yaw). Mean AHP for patients with a > +/-10 degree AHP was (-10.50 roll, -13.15 pitch, -27.30 yaw). There was a significant non-congruous response during subjective response to head posturing with most sensing their head as straight when physically not and vice-versa (p=0.00011,table).Conclusions Clinical AHP in patients with INS exists in all 3 dimensions of roll (lateral flexion), pitch (chin lift), and yaw (cervical rotation). Although the visual system may be causally related to the onset of an AHP in patients with INS due to an eccentric null zone, its persistence over time or after surgical intervention is likely due to a combination of visual (e.g. nystagmus, strabismus) and non-visual( e.g. abnormal egocentric localization and/or musculo-skeletal symmetry) factors.Layman Abstract (optional): Provide a 50-200 word description of your work that non-scientists can understand. Describe the big picture and the implications of your findings, not the study itself and the associated details. Utility of a cheiroscope to test simultaneous perception and fusion AuthorBlock: Ken Kakeue1, Miharu Mihara1, Atsushi Hayashi1 1Ophthalmology, University of Toyama, Toyama, Japan; DisclosureBlock: Ken Kakeue, None; Miharu Mihara, None; Atsushi Hayashi, None; Purpose The examinations of simultaneous perception and fusion using a synoptophore are often difficult in patients with strabismus, particularly young children, despite their importance before a strabismus surgery. Cheiroscopic tracing, which requires fusion and simultaneous perception, is used in young children for training of binocular vision function. The aim of this study was to investigate the utility of cheiroscopic tracing to test simultaneous perception and fusion.Methods The participants had a visual acuity of over 0.0 logarithm of the minimum angle of resolution (logMAR), and no history of amblyopia or neurological or musculoskeletal diseases. The study included 33 patients with strabismus, who could perform cheiroscopic tracing. Square line drawings of two sizes (20° and 6°) were used for cheiroscopic tracing. Patients were required to trace two pictures with each eye. We determined that patients had no simultaneous perception or fusion when they could not trace the pictures. Patients were categorized under two groups: intermittent exotropia (XT; n = 19; mean age, 9.8 ± 5.6) and esotropia (ET; n = 14; mean age, 10.2 ± 6.0). In addition, all patients were examined for simultaneous perception and fusion using a synoptophore. We compared the results of cheiroscopic tracing with those of synoptophore testing for simultaneous perception and fusion.Results Using a synoptophore, simultaneous perception was detected in 89.5% and 85.7% cases of the XT and ET groups, respectively, and fusion was detected in 73.7% and 71.4% cases of the XT and ET groups, respectively. Simultaneous perception or fusion did not differ significantly between the two groups. Seven patients with XT and four patients with ET had no simultaneous perception or fusion in the synoptophore test. Among those patients, six with XT were associated with suppression and two with ET were four years of age.Conclusions Eleven patients, who were detected with no simultaneous perception or fusion using a synoptophore, were included in this study. Cheiroscopic tracing was useful for checking the presence of simultaneous perception and fusion in these patients.Layman Abstract (optional): Provide a 50-200 word description of your work that non-scientists can understand. Describe the big picture and the implications of your findings, not the study itself and the associated details. Changes in the binocular coordination of saccadic eye movement and smooth pursuit in patients with acute acquired comitant esotropia after strabismus surgery AuthorBlock: Miharu Mihara1, Atsushi Hayashi1, Ken Kakeue1, Ryoi Tamura2 1Ophthalmology, University of Toyama, Toyama, TOYAMA, Japan; 2Integrative Neuroscience, University of Toyama, Toyama, Japan; DisclosureBlock: Miharu Mihara, None; Atsushi Hayashi, None; Ken Kakeue, None; Ryoi Tamura, None; Purpose Changes in saccadic eye movement (SEM) and smooth pursuit (SP) in patients with esotropia (ET) after strabismus surgery are largely unknown, because of few relevant reports. In previous reports, patients with early-onset ET are described with greater asymmetry in the gain in SP between temporal to nasal and nasal to temporal than that of patients with late-onset ET. We investigated the change in horizontal SP and SEM in patients with late-onset ET, particularly acquired comitant esotropia (ACE), comparing pre- to post-surgical data using an eye-tracker.Methods Horizontal SEM and SP of ten patients (mean age: 21.9 ± 8.4 years) with AACE were recorded using a video eye-tracker under binocular viewing before and after strabismus surgery in the non-dominant- eye. To study SEM, the participants were instructed to fixate their gaze on a target located in the center at the beginning of the test trial, and to fixate on a new target as rapidly as possible when it randomly appeared at either 18.3°-rightward or 18.3°-leftward. To study SP, the participants were asked to track a step-ramp target moving at ±6.1°/s horizontally as accurately as possible. The asymmetry in the adduction−abduction gain of each SEM and SP and the differences in the gain in each SEM and SP between the right and left eyes, that is, binocular coordination, were compared between the pre- and post-surgical data.Results After the surgery, the gain in SEM of the adduction in the both eyes and the abduction in the dominant-eye decreased. The asymmetry of adduction−abduction gain of SEM in each eye after surgery was significantly larger than that before surgery. The differences in the gain of SEM between both eyes in rightward and leftward decreased after surgery, but not significantly. The asymmetry of adduction−abduction after surgery in the gain in SP in each eye was smaller than that before surgery, but not significantly. After surgery, the left-right eye difference in gain of SP in the non-dominant eye direction decreased significantly.Conclusions Ocular alignment correction by strabismus surgery in patients with ACE results in an improvement in the binocular coordination of SP, not SEM, because SP needs visual feedback.Layman Abstract (optional): Provide a 50-200 word description of your work that non-scientists can understand. Describe the big picture and the implications of your findings, not the study itself and the associated details. Changes in saccadic eye movement (SEM) and smooth pursuit (SP) in patients with esotropia (ET) after strabismus surgery are largely unknown, because of few relevant reports. We investigated the change in the gain of horizontal SP and SEM in ten patients with acquired comitant esotropia (ACE), comparing pre- to post-surgical data using an eye-tracker. After the surgery, the gain in SEM was not significantly change. However, the left-right eye difference in gain of SP decreased significantly. That is, ocular alignment correction by strabismus surgery in patients with ACE results in an improvement in the binocular coordination of SP, because SP needs visual feedback. Measurement of Contrast Sensitivity using Vertical Vergence Eye Movements AuthorBlock: Deepa Dhungel1, Scott Stevenson1 1Optometry, University of Houston, Houston, Texas, United States; DisclosureBlock: Deepa Dhungel, None; Scott Stevenson, None; Purpose The current psychophysical methods for measuring the spatial contrast sensitivity function (CSF) require subject compliance, attention and active participation of the subject in the task. This poses a challenge for subjects with compromised communication or comprehension ability. Measuring vertical vergence, a reflex eye movement